Basic MediaWiki integration, library cleanup

Needs some cleanup, but this is working for the complete handshake. The
demo client in /test will get you back a valid OAuth access token.

done:
* integrate MWOAuthConsumer
* initial i18n

todo:
* tests

Change-Id: Ib6dd320b58f7ba2e4df3a8545cf9f3a790c2fa9b
Merge "Basic MediaWiki integration, library cleanup"